1. Field of the Invention
The present invention generally relates to a tree shaker pad and sling assembly associated with a nut tree shaker. Nut tree shakers include a shaking head having a clamping device engaging and clamping the tree to enable the tree shaker to impart the desired shaking forces to the tree for separating nuts from the tree twigs and branches. This type of device is well known for harvesting nuts from nut trees, fruit from fruit trees and the like. The present invention generally relates to a tree shaker pad and sling assembly in which the shaker pad includes a hollow resilient pillow filled with resilient members in the form of spherical rubber or elastomer balls.
2. Discussion of the Prior Art
The purpose of the nut shaker pads and slings is to transfer the shaking energy of the shaking head of the nut shaker to the nut tree without damage or injury to the bark on the tree trunk. Presently, two types of shaker pads are in use. One type of pad that is in use is a solid rubber pad of cylindrical or oval cross-sectional configuration with or without a hole extending axially through the center of the pad. The second type of pad that is in use is a rubber cylindrical hollow pillow filled with some type of granular material such as walnut shells, glass beads or small flat plastic pieces.
The solid rubber pad has the advantages of being simpler in construction thus making it simpler to build at less cost. The solid rubber pad is also safer in use as compared to filled pillow pads. The filled pillow pads have the advantages of better conformity the tree trunk when grasped by the shaker head which tends to spread the shaker head vibrator load over a larger area of the tree trunk and therefore does not stress or damage the bark on the tree truck as occurs when a more concentrated load is applied. However, the internal granular material or other medium which fills the pillow pad can get very hot due to friction created in the medium which fills the pillow pad when the shaking operation takes place. In some instances, it has been known that filled pillow pads will catch fire and explode during use which can create a hazardous situation that can not only damage the tree but also possibly injure an operator of the tree shaker. Various methods have been developed in an effort to cool filled pillow pads with the most common effort being the circulation of cooling air through the pads. However, another problem with the filled pillow pads is that when they are clamped tight they become very rigid or hard and thus eliminate some of the advantage of better conformity whereas the solid rubber pads maintain a greater degree of flexibility in a clamped position which tends to lessen the shock loads on the bark of the tree trunk.
My copending U.S. application Ser. No. 08/385,437 filed Feb. 8, 1995 for Cooling and Lubricating System for Nut Tree Shaker discloses a system for cooling and lubricating the slings and pad on a nut tree shaker. The following prior patents disclose other relevant developments in nut tree shakers and shaker pads and slings associated with nut tree shakers.
______________________________________ 3,123,965 4,768,332 3,178,875 4,893,458 3,780,510 4,921,073 4,128,986 4,932,195 4,254,608 5,103,625 4,521,468 5,385,006 4,757,674 Russian Patent No. 934,973 ______________________________________
While the several Compton patents disclose various shaker pads including shaker pads having a cooling feature, they do not disclose a filled cushion type pad. U.S. Pat. No. 4,521,468 to Brandt discloses a filled pillow shaker pad in which the granular material is disclosed as plastic bits impregnated with a high melting temperature lubricant. The plastic bits are disclosed as being short cylindrical rods or chips. This patent also states that the granular material filling the pillow may be coarse sand, metal particles or plastic bits and also mentions that broken walnut shell pieces have been used and indicates that it is desirable to loosen compacted material after each use by air or other fluid.
None of the prior patents disclose a filled pillow tree shaker pad having water or other liquid coolant circulating therethrough in which the filler medium for the pillow type tree shaker pad is filled with resilient members such as spherical resilient balls of rubber or other elastomers which better conform to the tree trunk and also maintain a degree of flexibility in the clamped position in view of their resiliency and, when released from the clamped position, the filler medium returns to their spherical shape to permit voids to develop between the balls which enables water or other coolant to migrate through the interior of the pillow pad thereby effecting cooling the pillow pad during use.